Retail gasoline prices in the United States may be erratic as investors guess on what happens next with OPEC, though pain at the pump is diminishing, AAA said. The motor club reports a national average retail price for a gallon of regular unleaded gasoline at $2.21 for Tuesday, relatively unchanged from one week ago and slightly higher than the national average reported for this date in 2015. AAA said the national average has dropped for several straight days, but a decline that usually comes late in the year has yet to emerge in part because of dynamics in crude oil prices. “Drivers may continue to see prices wobble up and down as traders speculate on the possibility of OPEC countries […]